The present invention generally relates to methods for the creation of an array of materials at known locations on a substrate surface, and more specifically to methods for the creation of an array of materials for screening for useful heterogeneous catalytic properties.
The discovery of new materials with novel chemical and physical properties often leads to the development of new and useful technologies. Over forty years ago, for example, the preparation of single crystal semiconductors transformed the electronics industry. Currently, there is a tremendous amount of activity being carried out in the areas of catalysis, superconductivity, magnetic materials, phosphors, nonlinear optics and high strength materials. Unfortunately, even though the chemistry of extended solids has been extensively explored, few general principles have emerged that allow one to predict with certainty composition, structure and reaction pathways for the synthesis of such solid state compounds, compositions or structures. Moreover, it is difficult to predict a priori the physical properties a particular three-dimensional structure will possess.
Clearly, the preparation of new materials with novel chemical and physical properties is at best happenstance with our current level of understanding. Consequently, the discovery of new materials depends largely on the ability to synthesize and analyze new materials, compounds, compositions or structures. Given approximately 100 elements in the periodic table that can be used to make such compositions consisting of three, four, five, six or more elements, the universe of possible new compounds remains largely unexplored. As such, there exists a need in the art for a more efficient, economical and systematic approach for the synthesis of possibly new compounds, compositions or structures (e.g., materials) and for the screening of such materials for useful properties, particularly materials useful for heterogeneous catalysis.
Pirrung, et al., have developed a technique for generating arrays of peptides and other molecules using, for example, light-directed, spatially-addressable synthesis techniques (see, U.S. Pat. No. 5,143,854 and PCT Publication No. WO 90/15070, incorporated herein by reference for all purposes; see also, Geysen et al, J. Immun. Meth. 102:259-274 (1987), incorporated herein by reference for all purposes). In addition, Fodor, et al. have developed, among other things, a method of gathering fluorescence intensity data, various photosensitive protecting groups, masking techniques, and automated techniques for performing light-directed, spatially-addressable synthesis techniques (see, Fodor, et al., PCT Publication No. WO 92/10092, the teachings of which are incorporated herein by reference for all purposes). Schultz et al., in U.S. Pat. No. 5,985,356 entitled xe2x80x9cCombinatorial Synthesis of Novel Materialsxe2x80x9d disclose methods for preparing and screening arrays of materials for combinatorial material science applications such as catalysis, and is incorporated herein by reference. See also, e.g., U.S. Pat. Nos. 5,288,514 and 5,424,186, incorporated by reference herein.
Solution-based methods, such as the sol-gel process, are widely used for the synthesis of inorganic materials. An example of one system for the formation of combinatorial libraries is disclosed in commonly owned co-pending U.S. patent application Ser. No. 09/156,827 entitled xe2x80x9cFormation of Combinatorial Arrays of Materials using Solution-Based Methodologiesxe2x80x9d, hereby expressly incorporated by reference. See also, WO 98/15969, hereby incorporated by reference. Also, of potential interest to the present invention are U.S. Pat. No. 5,959,297 xe2x80x9cMass Spectrometers and Methods for Rapid Screening of Libraries of Different Materialsxe2x80x9d, U.S. Pat. No. 5,585,136, xe2x80x9cMethod for Producing Thick Ceramic Films by a Sol Gel Coating Processxe2x80x9d, U.S. patent application Ser. No. 60/122,704 entitled xe2x80x9cChemical Processing Microsystems, Diffusion-Mixed Microreactors and Methods for Preparing and Using Samexe2x80x9d, and Choi et al., xe2x80x9cCombinatorial Methods for the Synthesis of Aluminophosphate Molecular Sieves,xe2x80x9d Angew. Chem. Int. Ed. 1999, 38, No. 19 (2891-2894), each of which are hereby incorporated by reference.
This invention provides methods for the synthesis of combinatorial libraries or arrays on or in suitable substrates by effectively utilizing a certain combination of steps. The invention can be used to make known materials or new materials. In addition, this invention provides a general route for the synthesis of arrays of transition metal and other oxides for screening for heterogeneous catalytic properties.
In one aspect, this invention provides a method for forming an array of supported materials for screening as catalysts by providing a first component (preferably a catalyst carrier or support in its solid state) and impregnating the first component with a second component (preferably a catalyst precursor delivered in a fluid medium). The steps are repeated to generate a plurality of impregnated materials. The impregnated materials preferably are separated into individual regions on a substrate, and treated to form an array having a plurality of different materials.
Materials that can be prepared using the methods of the present invention include, for example, supported catalyst materials. Once prepared, these materials can be screened for useful catalytic properties using techniques such as high throughput screening techniques.
In the context of catalyst material synthesis, it is thus believed that the present invention will yield materials that have a structure and reactivity more closely approximating those of bulk catalysts. The present invention also readily permits for the use of high throughput screens to identify good catalyst support materials. The present invention permits for the use of a broad variety of precursor solutions, the effect of the selection of which can be readily screened. Such precursor solutions (e.g., without limitation, nitrates, acetates, oxalates, halides, or mixtures thereof) can be prepared in relatively high concentrations, allowing for relatively high catalyst loading on the substrate.